Method and machine for making wiring strip



April 10, 1934. L. KALISCHER METHOD AND MACHINE FOR MAKING WIRING- STRIP Filed May 11, 1933 4 Sheets-Sheet 1 (JINVENTOR h- ATTORNEY April 10, 1934.

| KALISCHER 1,954,414

METHOD AND MACHINE FOR MAKING WIRING STRIP Filed May 11; 1933 4 Sheets-Sheet 2 IQ A ATTORNEY L. KALISCHER METHOD AND MACHINE FOR MAKING WIRING STRIP April 10, 1934.

4 Sheets-Sheet 3 I NVENTOF? ATTORNEY Filed May 11, 1935 April 10, 1934. V L. KALISCHER 1,954,414

METHOD AND MACHINE FOR MAKING WIRING STRIP Filed May 1.1, 1953 4 Sheets-Sheet 4 RUGGED! Paw; k nyvENToR A; ATTORNEY Patented Apr. 10, 1934 UNITED STATE METHOD AND MACHINE FGR MAKING WIRING STRIP 23 Claims.

This invention relates to a machine and method for making armored wiring strips by rolling the marginal portions of a flat ribbon of metal about a pair of spaced insulated wires. The method and machine are adapted for making such armored wiring strips in which the turned-over wire-covering margins of the metal ribbon are continuous and unbroken; but the invention has been made especially with the idea of providing an improved method and machine for making wiring strip of the kind described in my copending application Serial No. 568,900, filed October 15, 1931, in which the turned-over marginal per-- tions of the metal ribbon are not continuous but are cut away at points in the length of the strip where the strip is to be bent or connections made to the wires, so that armored sections of the wiring strip alternate with short unarmored sections which have only a narrow fiat part of the ribbon beneath the two wires. These unarmored sections of the wiring strip make it possible readily to make desired connections to the wires and to bend the strip at the unarmored points.

As the points where the strip in being installed is to be bent, or where connections are to be made to the wires, will vary for different installations, depending upon the conditions and re" quirements of each installation, the wiring strips must be made especially for each individual installation with the unarmored sections properly spaced at varying distances apart. It is desirable, therefore, to have a machine for forming the wiring strip which is compact and portable so that it may be taken to and set up in or near the room or place to be wired. One of the objects of the present invention is to provide such a portable machine by which a high grade product may be made conveniently and rapidly.

A full understanding of the invention can best be given by a detailed description of a machine embodying the apparatus features of the invention in the form now considered best and adaped for carrying out the method, and such a description will now be given in connection with the accompanying drawings illustrating such a machine.

In said drawings:-

Fig. 1 is a side elevation of the machine;

Fig. 2 is a central vertical longitudinal sec" tion through the machine; 7

Fig. 3 is a sectional plan View taken on line 3-3 of Fig. 2 with parts shown in plan, other parts broken away and other parts omitted.

Fig. 4 is a plan view of the machine with a part of the casing and some other parts broken away and some parts omitted;

Fig. 5 is a section on the line 5-5 of Fig. 2;

Figs. 6, 7, 8, 9 and are enlarged detail sectional views on the line 6-6, 7-7, 8-8, 9-9 and 10-10, respectively, of Fig. 3;

Fig. 11 is a perspective view of the stripper bar and its wire retaining plate, shown separated;

Fig. 12 is a perspective View of a piece of a completed wiring strip with portions of the insulated wires broken away; V

Fig. 13 is a plan view of two sections of wiring strip which have been positioned to extend at right angles to each other; and

Fig. is is a view similar to Fig. 13 but showing a partly broken away corner cover attached.

The strip cutting, feeding and forming parts of the machine are mounted within a casing com posed of two side pieces held in spaced relation by three shoulder bolts 21, and a sheet metal cover piece 22 which forms the top and ends of the casing. The side pieces are recessed along their inner peripheries to receive the edge of the sheet metal piece 22, which is made of spring steel or the like so that it can be snapped into and out of engagement with the side pieces when it is desired to reach the interior of the casing. The lower edge of the end portions of the piece 22 are turned inward slightly and the recesses in the peripheries of the side pieces are similarly curved inwardly so that such edges and recesses interlock and releasably hold the piece 22 in the position shown in Fig. 2. When it is desired to remove the cover piece 22, one or both ends are pulled outwardly to release the lower edges thereof and then the cover piece is lifted off the machine. The machine is supported by four legs 23, the upper ends of which are detachably inserted in sockets in inwardly enlarged parts 24 of the side pieces 20.

Extending between the side pieces 29 is a supporting or base plate 25 on which certain of the operative parts of the machine are mounted and over which the ribbon and wires are fed through the machine past the forming devices. This base plate is most desirably removably mounted, being, as shown, supported on flanges 26 extending inward from the side walls and secured by screws 27. The metal ribbon A and the two insulated wires B enter the machine through an opening 30 in the casing wall at one end of the machine, and the wiring strip C is discharged through an opening 31 in the end wall of the casing at the opposite end of the machine, the openings being located so that the metal ribbon may pass straight through the machine resting on the base plate with the wires directly above the ribbon. The ribbon may be drawn from a reel 32 which may be journalled in brackets attached to one pair of the legs 23, and the wires may be drawn from a reel 33 journalled in brackets attached to the other pair of legs.

The metal ribbon is fed through the machine over the base plate 25 by two pairs of feeding rolls 35, 36 and 37, 38. Rolls 35 and 36 are located near the entrance end of the machine and are mounted with their axes horizontal, the lower roll 36 extending through an opening 39 in the base plate 25 to engage the under side of the ribbon, and the upper roll being mounted to bear on the upper side of the ribbon directly over the roll 36. The rolls 37 and 33 are similarly mounted near the discharge end of the machine, the lower roll extending through an opening 39' in the plate 25 to engage the under side of the ribbon and the upper roll 37 being mounted to engage the ribbon directly over the roll 38. The two pairs of feed rolls are driven at the same peripheral speed. Most desirably, and as shown, only the bottom roll of each pair is driven, and these bottom rolls have their peripheral surfaces knurled or other wise suitably roughened for insuring the desired grip on the ribbon pressed against it by the cooperating upper roll. In the particular machine shown, the feed rolls are driven by hand from a shaft 40 which is provided with a hand crank 41 outside of the machine casing, and carries a gear 42 inside the casing. The roll 36 is driven from the gear 42 through an intermediate 43 which meshes with a gear 44 on the roll shaft, and similarly, the roll 38 is driven from gear 42 at the same peripheral speed as the roll 36 through an intermediate 45 meshing with a gear 46 on the roll shaft. The gear ratio is desirably such that the angular speedof the feed rolls will be less than thatof the crank shaft 40 so as to lessen the force required to drive the machine, thus insuring in hand operation a smoother more uni form movement, and because it is desirable that the ribbon shall be fed through the machine at acomparatively slow rate.

The upper feed rolls 35 and 37 should be set so as to bear firmly against the top surface of the ribbon and press the ribbon against the lower feed rolls 36 and 38. The rolls are most desirably rigidly mounted, and in order to provide for adjusting this pressure and to adapt the machine for ribbons of varying thickness, the upper rolls are mounted so as to be vertically adjustable. For this purpose each of the upper rolls 35 and 37 is mounted to turn on a shaft 50 between collars 51 held in position by set screws as indicated-in Fig. l, and this shaft 50 is eccentrically mounted by'means of eccentric studs 52 extending from the ends of the shaft into hearings in bearing blocks 53 which are removably secured as by screws 54 to the base plate 25. The shaft 50 may be turned to force the feed roll downward by adjusting screws 55, one at each end of the shaft, each of'which bears on a flattened surface 56 of the shaft.

The ribbon forming devices'by which the marginal portions of the ribbon are turned up and over and down between the two spaced wires are mounted on the plate 25 between the two pairs of feed rolls. These devices include a series of successively acting pairs of forming rolls 60, 61, 62 and 63,and a fixed central forming member or bar 64. The forming rolls are idle rolls mounted on vertical stub shafts 65, the lower ends of which are screwed into threaded openings in the base plate 25, and each roll sets down into a shallow depression in the face of the base plate, as shown in the sectional views, Figs. 7 to 9. The rolls are peripherally grooved, and the two rolls of each pair are mounted on opposite sides of the path of movement of the metal ribbon. The number of pairs of forming rolls may be varied, but I have found it most desirable to use four pairs of these rolls as shown. With a lesser number of pairs I find that each pair is required to eifect too much bending of the metal strip for satisfactory operation, and a greater number of pairs unnecessarily increases the length of the machine.

The forming rolls are mounted with the spaces between the rolls of successive pairs progressively decreasing in the direction of travel of the metal ribbon, so that the rolls provide a gradualy narrowing pass through which the ribbon is moved. As the ribbon fed by the feed rolls comes between the first pair, 60, of forming rolls, the extreme outer marginal, or edge, portions of the ribbon are bent slightly upward as indicated by Fig. 6. By the second pair, 61, of forming rolls, the edges of the ribbon are moved further upward and a wider part of each marginal portion of the ribbon is subjected to the forming action, as shown by Fig. '7. By the next pair, 62, of forming rolls a still wider part of the marginal portions of the ribbon is acted upon and the edges of the ribbon are moved inward over the tops of the wires as shown by Fig. 8. As the ribbon passes between the last pair, 63, of the forming rolls a further inward part of each marginal portion of the ribbon is turned upward and the extreme outer marginal portions are moved downward between the Wires as shown by Fig. 9. At the start of the forming operation the two wires are spaced more widely apart than in the completed wiring strip, and they gradually move inward toward each other as they move forward with the metal strip and as the marginal portions of the strip are wrapped about them, as clearly shown by Figs. 3 and 6 to 9.

The grooves of the forming rolls 60, 61 and 62 should be of a radius somewhat greater than the radius of the wrapped portions of the completed wiring strip so as to avoid any clamping of the marginal portions of the ribbon against the wires in passing between these rolls. The grooves of the last pair 63 of forming rolls should, however, most desirably be semi-circular grooves of a radius equal to that of the rolled-over marginal portions of the completed wiring strip so as finally to form the strip margin portions tightly against the 1 wires. Most desirably, the radii of the peripheral grooves of the forming rolls are progressively shorter from the first pair to the last pair 63 of such rolls.

A roll 66, having a peripheral portion which is tapered, or wedge-shaped, in cross-section, is mounted on a horizontal shaft 67 which extends at right angles to the direction of movement of the wiring strip in position so that the wedgeshaped periphery of the roll extends down between the wires and between the turned down edge portions of the metal ribbon to press these portions outwardly against the wires. This spacing roll, which is desirably, but not in all cases necessarily, provided. is best located just beyond the line between the forming roll 63.

A final forming and sizing operation is performed by the feed roll 37, which has its periphery formed with two grooves 68 of a depth and Width and so spaced as to receive and give a final 1:3

finishing pressure to the rolled marginal portions of the ribbon about the wires. The central rib or part 69 of the roll serves to press the rolledover edges of the ribbon downwardly and outwardly against the wires, and it also cooperates with the bottom feed roll 38 to feed the strip. The width of the central rib 69 will be determined by the spacing of the wires and the space between the rolled marginal portions of the ribbon.

It will be observed that in the forming operation progressively wider marginal portions of the metal ribbon are acted on as the ribbon advances past the forming devices, the extreme outer marginal or edge portions of the ribbon being first turned to curve upwardly by the rolls 60, and the upward curving of the margins being extended progressively inward as the ribbon advances past the rolls 61, 62 and 63, and as the more inward marginal portions are curved upward the previously curved outer marginal portions move inward and then downward about the wires; and that, during the forming operation, the wires are drawn along in gradually approaching paths, being held more widely spaced apart by the forming bar at the beginning of the operation, and moving gradually toward each other as progressively wider marginal portions of the ribbon are acted on by the forming rolls, until, as the rolls 63 are reached, the wires at their final spacing are separately enclosed and gripped by the rolled over marginal portions of the ribbon.

The ribbon A should be of a metal which is fairly soft and easily bent, and which is substantially non-resilient so that it will take a set in the form to which it has been bent, A rather soft aluminum or aluminum alloy is generally used. In the completed wiring strip, the insulated wires are gripped by the rolled over margins of the ribbon.

If the metal ribbon is very soft and easily bent, it may be suflicient to have the wires suitably guided to reach the first pair of forming rolls, spaced, as shown in Fig. 6, considerably wider apart than they are in the completed wiring strip; but usually it is best, and for less easily bent ribbon it is necessary, to provide means for further guiding the wires and for holding them in position against pressure of the margins of the ribbon as the margins are being bent upward and inward. The forming bar 64 serves this purpose, and it also serves to hold the ribbon down on the plate 25, preventing it from rising as its edge portions are turned upward by the forming rolls and 61.

The forming bar 64 is connected to and held in position by a cross-bar which is detachably secured to the base plate at the entrance end of the machine. The cross-bar has the central portion of its under side recessed to a depth slightly greater than the thickness of the ribbon, as shown at 71 in Fig. 11, and the width of this recess is s1ight- 1y greater than the width of the ribbon, so that the shoulders at the ends of the recess serve to guide the ribbon. The cross-bar '70 has also two wire guiding recesses '72 extending upward from its recess '71 and spaced apart a distance substantially equal to the greatest width 1e forming bar 64. The end of the forming bar connected to the cross-bar is spaced from the surface of the base plate a distance slightly greater than the thickness of the ribbon. Its connection to the cross-bar is such as to permit a slight lateral and vertical swinging movement of the bar, and its free end rests on the base plate when there is no ribbon in the machine, or on the ribbon when there is a ribbon in the machine.

The forming bar has an opening '73 through which the feed roll 35 engages the ribbon, and the bar extends past the forming rolls 60 and 61 and may end a short distance beyond the rolls 61. From the rolls 60 the bar tapers horizontally inward on both sides so as to permit the wires, one on each side of the bar, to approach each other as they move toward and beyond the forming rolls 61 and as the margins of the ribbon are turned about them. The bar should be of such width between the forming rolls that, While it serves to hold the wires suitably in position against the upward and inward pressure or" the margins of the ribbon as the margins are being turned by the rolls, there will be no such clamping of the wires between the rolls and the bar as would cause any considerable retarding friction between the wires and the bar. For holding the wires down in proper position during the first part of the forming operation, during which the outer margins of the ribbon are being turned upward by the rolls 6S and 61, the forming bar has wire retaining flanges, one on each side, extending outward over the paths of the wires. These flanges are pro" vided, in the construction shown, by the laterally extending edge portions of a wire retaining plate '74 secured on the bar and having an opening 5 for the feed roll 35 registering with the opening 73 in the forming bar.

The wiring strip tends at times to bend laterally somewhat as it leaves the feed rolls 3'? and 38. To prevent such bending, a pair of deeply grooved guide rolls '76 is provided mounted on vertical stud shafts, one roll on each side of the path or" the wiring strip a short distance beyond the feed rolls. These rolls, the grooves of which fit closely about the two tubular portions of the wiring strip, apparently serve to correct the tendency of the strip to bend.

The cut-out device for cutting marginal. portions out of the metal ribbon at the points where the wiring strip is to be bent, or connections made to the wires, is located at the entrance end of the machine in advance of the first pair of feed rolls. The cut-outs may be of rectangular form or of other suitable or desired form, but are most desirably of trapezoidal form with their ends slanting outwardly so that the edge of each marginal portion of the ribbon at the rear end of each cutout slants backward toward the edge of the ribbon. This is of advantage in that it makes easier the entrance of these edges between the forming rolls. There is no need for the forming operation to have the edges of the marginal portions at the front ends of the cut-outs slant forward, but for the appearance of the wire strip, it is desirable to have the cut-outs symmetrical. The slanting edges at the ends of the cut-outs are also of advantage in the finished wiring strip for the reason that when the wires are turned outward at the cut-out portions of the wiring strip there is an easier bend of the wires and less danger of damaging the insulation.

The cut-out device comprises a die plate formed by a part of the base plate 25 having two die openings 80 of the desired trapezoidal shape, and a vertically reciprocable cutter block 81 having two downwardly projecting cutters or punches the cutter block into vertical holes in the guide blocks. The cutter block is also guided by a stem 86 which extends upward through an opening in a cross-bar 8'7 and through an opening 83 in the cover plate 22 and is provided at its upper end with a knob 89 by pressure on which the cutter block may be depressed against the action of a spring 90 which normally holds the cutter block in its elevated position as shown in Figs. 2 and 5.

In order that the wires B shall not interfere with the action of the cutters 82, they are passed through openings 91 in the cutter block located just above the bottom of the cutters or punches 82. The die openings 80 are formed with outwardly and downwardly flaring sides so that the cut-out pieces of the ribbon will be free to fall down through the openings. The narrowed shank portion of the forming bar 64 which extends through the recess in the under side of the cutter block between the cutters 82 serves as a stripping bar to hold the ribbon against being lifted by the cutters as they rise after a cutting operation.

When a ribbon end is introduced into the machine, the marginal portions for a distance from the end of the strip are cut away to provide a narrow end portion or tongue of sufficient length to extend past at least the last two pairs of forming rolls and into the bite of the feeding rolls 37 and 38. It is also desirable that at the end of the formed wiring s rip there shall be a narrow end portion of the metal ribbon and projecting free ends of the wires. To aid in properly positioning the introduced end of the ribbon with relation to the die openings 80 for the first cutting operation, a sight opening 92 is provided in the bar 64 which may be viewed through the cover plate opening 88. Additional sight openings may be provided at a point further along in the direction of feed, but I have found that after the first cutting operation the distance to advance the ribbon for making the further desired cuts can readily be gauged without additional sight openings.

When starting up the machine, the end of the ribbon is entered through the opening 30 in the entrance end wall of the machine casing and is advanced beneath the cross-bar '70 and beneath the shank of the forming bar 64 until properly positioned over the die openings. The cutter is then operated, and the ribbon is then pushed further into the machine and the cutter operated again, and this operation, if necessary, is repeated again or until a narrow end portion or tongue of the desired length at the end of the ribbon has been formed. The end of the tongue will then be between the first feeding, or pushing, rolls and 36, and by turning the crank 41 these rolls will be operated to further feed the ribbon into the machine until the end of the tongue comes into the bite of the second pair of feeding rolls 37 and 38. During this movement, if the tongue at the end of the ribbon is of about the length above stated and as shown by Fig. 3, the marginal portions of the ribbon just beyond the tongue will have been acted on by the forming rolls and 61. These forming rolls do not ofier any great resistance to the forward movement of the ribbon sufficient to interfere with the feeding of the ribbon by the pushing action of the feed rolls 35 and 36.

The ends of the wires might be threaded into position in the machine before the end of the ribbon is entered and positioned as described. It is more convenient, however, to enter the ends of the Wires after the end of the ribbon has been positioned with its forward reduced end in the bite of the feed rolls 3? and 38. The ends of the wires are passed through the opening 30 and are threaded through the wire recesses '72 in the cross-bar and through the openings 91 in the cutter block, and past the tapered end portion of the forming bar 64 beneath the edge portions of the wire retaining plate '74, and to or somewhat beyond the forming roll 63 so that the ends of the wire, which are fed through the machine only as they are gripped by the rolled-over marginal portions of the metal ribbon, will be in position to have the ends of the first marginal portions of the ribbon wrapped about them. The ribbon and the wires being thus positioned, the feed rolls are operated to advance the ribbon past the forming devices, by which the marginal portions of the ribbon are wrapped about the previously positioned wires. By the time the full width end portion of the ribbon has reached the last forming rolls 63, the wires will have been gripped by the rolled-over marginal portions of the ribbon and will thereafter be drawn forward With the ribbon. The operation of the forming rolls and of the spacing rolls 66 and of the feed roll 37 in functioning as a final forming and sizing roll has been fully pointed out and need not be further explained.

I have found it most desirable in operating the machine to have the upper feed roll 35 of the first pair of feed rolls set so that the ribbon will not be gripped very tightly by these rolls, and to rely mostly on the second, or pulling, pair of feed rolls 3'7 and 38 to draw the wiring strip past the forming devices. The roll 3'7 should be set so that the ribbon will be gripped tightly between it and its coacting roll 38 and be positively fed thereby. The adjustment of the roll 35 is best, as I find, when the ribbon is rather lightly gripped between it and its co-acting bottom roll 36, sufficiently to push the ribbon with force enough to move the end marginal portions past the feed rolls 60 and 61, but so that it is possible for the ribbon to slip slightly between these feed rolls where the second pair of feed rolls is acting on the ribbon.

If it is desired to make cut-outs in the ribbon of any desired length in excess of that made by a single operation of the cut-out device, this may readily be accomplished by repeated operation of the cut-out device, the strip being moved forward a short distance between such repeated operations.

In order that the operator may know when the ribbon has been fed the proper distance to bring the place where the next cut-out is to be made over the die openings 80, and so that successive cut-outs may readily be made at the desired variably spaced points in the ribbon, the machine is provided with a feed-indicating device adapted to show the distance that the ribbon has been moved through the machine. For this purpose any suitable measuring or distance indicating device, such as the device indicated at 93 in Fig. 3, may be provided and arranged to be driven from the shaft of the feed roll 39 or otherwise in time with one of the driven feed rolls. The indications of this device enable the operator, when operating the machine after each cut-out operation, to know the length of ribbon which has been advanced beyond the die openings. He will thus know just when to stop for making the next cut-out to provide an unarinored section of the wiring strip following each predetermined length of armored section of the strip.

A section of a completed wiring strip, showing a cut-out, or unarmored, section and parts of the two adjacent armored sections, is illustrated in Fig. 12. To make a right-angle turn in the plane of the wiring strip, for example, the metal ribbon is cut across, as along the line aa at about the mid-point of the unarmored section. The adjacent armored sections are then turned at right angles to each other to bring the parts into the position shown in Fig. 13 with the cut ends or" the metal ribbon overlapping as shown and thereby electrically connecting the metallic armor of the adjacent sections. The exposed sections of the wires are then covered by an angle piece 95 of suitable material, held in place by screws 96. Right-angle turns in directions perpendicular to the plane of the wiring strip are readily made, either with or without cutting the metal ribbon, as explained in my co-pending application hereinbefore referred to.

What is claimed is:

1. The method of making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, which comprises advancing the ribbon endwise, advancing the wires on the ribbon spaced more widely apart than they are in the completed wiring strip and causing them to move in gradually approaching paths to their final spacing, and wrapping the marginal portions of the ribbon about the advancing and approaching wires by first bending the outer marginal portions to curve upwardly and, as the ribbon advances, extending the bending and upward curving of the margins progressively inward and moving the curved outer marginal portions inward over and downward about the gradually approaching Wires.

2. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, forming means for wrapping the marginal portions of the advancing ribbon about the wires, and wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, the forming means comprising members shaped to act on progressively wider marginal portions of the ribbon to bend them upward and to move the first bent outer marginal portions inward and downward about the wires.

3. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, wire guiding means for guiding the wires to the ribbon spaced more widely apart than they are in the completed wiring strip, and forming means past which the ribbon and wires move including a tapered inner forming member for guiding the wires to move in gradually approaching paths to their final spacing and outer forming members for wrapping the marginal portions of the advancing ribbon about the wires, said outer forming members being shaped to act on progressively wider marginal portions of the ribbon to bend them upward and to move the first bent outer marginal portions inward and downward about the wires, and the tapered inner forming member having outwardly projecting flanges to extend over the wires.

4. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of 5 which are wrapped about the wires, comprising ribbon feeding means, forming means for wrapping the marginal portions of the advancing ribbon about the wires, and wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, the forming means comprising a series of pairs of spaced peripherally grooved rolls, the spacing of the rolls of successive pairs decreasing in the direction of travel of the ribbon, whereby the rolls form a gradually narrowing pass in which as the ribbon advances its marginal portions are bent upward starting at the outer portions and the binding is extended progressively inward and the outer marginal portions are moved inward and downward about the wires.

5. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, forming means for wrapping the marginal portions of the advancing ribbon about the wires, and wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, the forming means comprising a series of pairs of spaced peripherally grooved rolls, the spacing of the rolls of successive pairs decreasing in the direction of travel of the ribbon, whereby the rolls form a gradually narrowing pass in which as the ribbon advances its marginal portions are bent upward starting at the outer portions and the bending is extended progressively inward and the outer marginal portions being moved inward and downward about the wires, the peripheral grooves of the forming rolls of the last pair being substantially semicircular and of a radius substantially equal to that of the rolled margins of the ribbon of the completed wiring strip, and the rolls of the preceding pairs having grooves of greater radius.

6. A machine for making armored wiring strip as claimed in claim 5, in which the forming rolls are idle rolls mounted on vertical axes.

7. A machine for making armored wiring strip consisting of a pair of spaced insulated Wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, forming means for wrapping the marginal portions of the advancing ribbon about the wires, and wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, the forming means comprising members shaped to act on progressively wider marginal portions of the ribbon to bend them upward and to move the first bent outer marginal portions inward and downward about the wires, and including a pair of spaced peripherally grooved rolls mounted to rotate about vertical axes, the peripheral grooves of said rolls being semicircular and of a radius equal to the radius of the rolled marginal portions of the ribbon of the completed wiring strip.

8. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, forming means for wrapping the marginal portions of the advancing ribbon about the wires, wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, the forming means comprising members shaped to act on progressively wider marginal portions of the ribbon to bend them upward and to move the first bent outer marginal portions inward and downward about the wires, and including a pair of spaced peripherally grooved rolls mounted to rotate about vertical axes, the peripheral grooves of said rolls being semicircular and of a radius equal to the radius of the rolled marginal portions of the ribbon of the completed wiring strip, and a roll having a tapered peripheral portion mounted beyond but close to said pair of peripherally grooved rolls to rotate about a horizontal axis at right angles to the direction of movement of the ribbon for pressing the downwardly turned marginal portions of the ribbon downwardly and outwardly against the wires.

9. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising a pair of upper and lower coacting feeding rolls for pulling the ribbon past the forming means, and wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, and forming means for bending the marginal portions of the advancing ribbon progressively to extend upward, inward and downward about the wires, the upper feeding roll having its periphery formed with two grooves of such width and so spaced as to receive and give a final finishing pressure to the rolled marginal portions of the ribbon, the central part of the roll between the grooves serving to press the rolled-over edges of the ribbon downwardly and outwardly against the wires and to cooperate with the lower feed roll in pulling the ribbon past the forming means.

10. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising a pair of coacting upper and lower feeding rolls for pulling the ribbon past the forming means, wire guiding means, forming means for bending the marginal portions of the advancing ribbon progressively to extend upward, inward and downward about the wires, and a roll having a tapered peripheral portion mounted between said forming means and said feeding rolls to rotate about a horizontal axis at right angles to the direction of movement of the ribbon for pressing the downwardly turned marginal portions of the ribbon downwardly and outwardly against the wires, the upper feeding roll having its periphery formed with two grooves of such width and so spaced as to receive and give a final finishing pressure to the rolled marginal portions of the ribbon, the central part of the roll between the grooves serving to press the rolledover edges of the ribbon downwardly and outwardly against the wires and to cooperate with the lower feed roll.

11. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising a pair of upper and lower coacting feeding rolls for pulling the ribbon past the forming means, wire guiding means, and forming means for wrapping the marginal portions of the advancing ribbon about the wires, the upper feeding roll having a peripheral portion of a width to fit between the rolled marginal portions of the ribbon to press the downwardly extending marginal portions of the ribbon downwardly and outward- 1y against the wires and to cooperate with the lower feeding roll.

.12. A machine for making armored wiring strip consisting of a pair of spacedinsulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, wire guiding means, forming means for wrapping the marginal portions of the advancing ribbon about the wires, and means for pressing the downwardly extending marginal portions of the ribbon downwardly and outwardly against the wires.

13. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising spaced pairs of upper and lower coacting ribbon feeding rolls, and forming devices between said pairs of feeding rolls for wrapping the marginal portions of the advancing ribbon about the wires.

14. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising spaced pairs of upper and lower coacting ribbon feeding rolls, and forming devices between said pairs of feeding rolls for wrappingthe marginal portions of the advancing ribbon about the wires, the second pair of feeding rolls being set to grip the ribbon tightly and feed it positively and the first pair of feeding rolls being set to grip the ribbon more lightly to permit the ribbon to slip between the rolls.

15. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising spaced pairs of upper and lower coacting ribbon feeding rolls, and forming devices between said pairs of feed rolls for wrapping the marginal portions of the advancing ribbon about the wires, the feeding rolls being rigidly mounted and one roll of each pair being adjustable toward its cooperating r011.

16. In a machine for making armored wiring strip, the combination with forming means for wrapping marginal portions of a metal ribbon about spaced insulated wires, of apair of upper and lower coacting ribbon feeding rolls for pulling the ribbon past the forming means, said rolls being rigidly mounted and the upper roll being mounted to rotate on a shaft adjustable about an axis eccentric to the shaft, and adjustable means engaging said shaft to hold the upper roll at the desired spacing from the lower roll.

17. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising spaced pairs of upper and lower coacting ribbon feeding rolls, and forming devices between said pairs of feed rolls for wrapping the marginal portions of the advancingv ribbon about the wires, the upper roll of the second pair of feeding rolls having its periphery formed with two grooves of such width and so spaced as to receive and give a final finishing pressure to the rolled marginal portions of the ribbon about the wires.

18. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, wire guiding means, grooved forming rolls for bending the edges of the ribbon upwardly against the wires, and a pair of deeply grooved forming rolls for bending inner marginal portions of the ribbon upwardly against the wires til and for moving the previously bent outer marginal portions of the ribbon inwardly over and downwardly about the wires, and means for pressing the downwardly extending edges of the ribbon downwardly and outwardly against the wires.

19. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising cutting means for cutting out opposite marginal portions of a ribbon, and means for wrapping the uncut marginal portions of the ribbon between the cutouts about a pair of insulated wires.

20. A machine for making armored Wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising ribbon feeding means, wire guiding means, means for cutting out opposite marginal portions of the ribbon spaced lengthwise of the ribbon at desired variable distances apart, forming means to which the ribbon is advanced from the cutting means for wrapping the uncut marginal portions of the ribbon between the cut-outs about the wires, and a feed indicating device for showing the distance the ribbon is advanced after each cutting operation.

(21. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions oi": which are wrapped about the wires, comprising ribbon feeding means, cutting means for cutting out opposite marginal portions of the ribbon, forming means for wrapping the marginal portions of the advancing ribbon between the cut-outs about the wires, and wire guiding means for guiding the wires to move in gradually approaching paths with the ribbon past the forming means, the forming means comprising peripherally grooved for ling rolls arranged in pairs to provide a gradually narrowing pass in which as the ribbon advances its marginal portions are bent upward starting at the outer portions and the bending is extended progressively inward and the outer marginal portions are moved inward and downward about the wires.

22. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions or" which are wrapped about the wires, comprising ribbon feeding means, wire guiding means for guiding the wires to hold them in gradually approaching paths, forming means for wrapping marginal portions of the advancing ribbon about the gradually approaching wires, the forming ileans providing a gradually narrowing pass in which as the ribbon advances its marginal portions are bent upward starting at the outer portions and the bending is extended progressively inward and the outer marginal portions are moved inward and downward about the wires, and cutting means in advance of the forming means for cutting out opposite marginal portions of the ribbon of trapezoidal form having outwardly slanting ends.

23. A machine for making armored wiring strip consisting of a pair of spaced insulated wires and a metal ribbon the marginal portions of which are wrapped about the wires, comprising means providing a supporting surface over which the ribbon is advanced, cutting means for 100 cutting out opposite marginal portions of the ribbon at desired variable intervals, a pair of cooperating upper and lower ribbon feeding rolls for engaging the ribbon beyond the cutting means, means for guiding the wires past the cutting means to the ribbon spaced more widel apart than they are in the completed wiring strip, forming means beyond said feeding rolls including a tapered inner forming member extending over the ribbon for guiding the wires to move in gradually approaching paths to their final spacing and outer forming members for wrapping the marginal portions of the ribbon between the cut-outs about the gradually approaching wires, and a second pair of upper and lower cooperating feeding rolls beyond the iorming means for positively gripping the ribbon between its rolled-over marginal portions enclosing the wires. 

